On Tuesday, April 23, Valve will be converting Team Fortress 2 to use the VPK file system introduced in Left 4 Dead instead of GCF. Most of you probably already heard about this, but you might not know the full implications. Not only will every current guide and tutorial telling where to find certain files be wrong forever, but you will not be able to access the TF2 configuration in Source SDK. Which means all mapping work will grind to a halt until an alternative is provided. We've already seen this happpen to Day of Defeat: Source and Half-Life 2: Deathmatch when they were converted, and so far there is no official word as to how soon we will get the use of our tools back, and in what form. The most likely scenario is that the SDK will eventually be removed altogether and replaced with a collection of "Authoring Tools" for each game. Knowing Valve, though, it could be a long time before they get around to doing it. If they have something else up their sleeves, like a brand-new SDK, it could be an even longer wait. So to everyone who has work they wanted to get done on their maps: You have one week to finish it. Judging by how quickly next Saturday's gameday filled up, I'm not the only one who realized this.